Advent 2020 week 2-PEACE

Isaiah 9 powerfully describes the spectacular reign of Messiah on earth, including the identifier "Prince of Peace". Yet Jesus surprises His inner circle of followers with the answer to His rhetorical question, "Do you think I came to bring peace on earth? by asserting, "No, I tell you, but division". Why was the first Advent of Christ so different from the OT prophesies?